He said this was “fully funded”, but the small print revealed that the government’s new teachers’ pay grant will still leave schools having to find the first 1 per cent out of their existing resources.

The DfE argued that schools would have budgeted for this as it was something they would have “anticipated under the previous public sector pay cap”.

Now it has emerged that some schools did not budget for a 1 per cent pay rise in 2018-19 because of the financial pressure they were already under.

The NAHT heads' union told Tes that it has been approached by schools in this situation, which said they would have to make cuts if they are to give teachers the full increase.

Schools forced to make 'impossible choices'

NAHT general secretary Paul Whiteman said: “Many struggling schools will have to make heartbreaking decisions to find the 1 per cent, forced into an impossible choice between paying their staff the amounts recommended and making yet more damaging cuts in the middle of a recruitment and retention crisis.”

Mr Whiteman added: “It is somewhat disappointing that the government has ‘assumed’ schools have already budgeted for a 1 per cent pay rise for their staff, given that only a few months ago the Education Policy Institute published a report on school funding that concluded that for two in five state-funded mainstream schools this would be unaffordable.”

The Department for Education declined to comment on schools that had not budgeted for a 1 per cent pay rise.